1. Field of the Invention
The invention relates to a baggage case, more particularly to an ergonomic wheeled baggage.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional ergonomic upright wheeled baggage 50, as disclosed in U.S. Pat. No. 5,630,521, is shown to include a main body 1, two front wheels 2 (only one is visible), two rear wheels 3 (only one is visible), and a retractable handle 4. The main body 1 has a front side 101, a rear side 102, a top side 103, a bottom side 104, and two lateral sides 105. Each of the front and rear sides 101, 102 is inclined at an angle θ with respect to a line 5 perpendicular to a substantially horizontal supporting surface 6, such as the ground. The top and bottom sides 103, 104 are substantially parallel to the supporting surface 6.
When the conventional wheeled baggage 50 is pushed or towed by a user on the ground, all four wheels are in contact with the ground, so that an additional force for tilting the conventional wheeled baggage 50 need not be exerted by the user. Further, since the conventional wheeled baggage 50 is configured as a parallelogram, its center of gravity is shifted rearwardly and away from the front wheels 2. When the conventional wheeled baggage 50 is pushed or towed by the user along an uneven surface, it will not tip over even if the front wheels 2 are chocked.
Although the aforementioned conventional wheeled baggage 50 can minimize the load borne by the user during pushing or towing of the baggage case 50, it has the following drawbacks during use:
1. Since the front and rear sides 101, 102 of the main body 1 are inclined rearwardly, the conventional wheeled baggage case 50 occupies a substantial space.
2. Since the front and rear sides 101, 102 of the main body 1 are inclined rearwardly, when the conventional wheeled baggage case 50 is in the still position, it is easily tipped rearwardly by an external force (F).
Another conventional wheeled baggage case 60 is shown in FIG. 3 to include a main body 7, four wheels 8 (only two are visible), two of which are disposed in front of the main body 7, and the other two of which are disposed at the back of the main body 7, and a handle 9. The main body 7 has a vertical front side 701, a rear side 702 parallel to the front side 701, a horizontal top side 703, a bottom side 704 parallel to the top side 703, and two lateral sides 705. When the conventional wheeled baggage case 60 is pushed, all four wheels 8 are in contact with the ground. However, since the conventional wheeled baggage case 60 has a rectangular configuration with the center of gravity located along a central line thereof, when the conventional wheeled baggage case 60 is pushed along an uneven surface, it is easily tipped over.